Teacher and presenter Rick Marshall gives his list of top tips when it comes to giving an engaging talk on physics to students
Research may be a mixture of 10% inspiration and 90% perspiration but there is no doubt that it is exciting and rewarding. Sharing the thrill and the intellectual fruits of your work with the next generation of potential physics undergraduates brings its own benefits, not least of which is that it is good fun. Here’s my best advice for how to give an inspiring presentation about physics to school students who are in that all-important 16–18 age range when they may well be deciding whether to study the subject at university.
Your talk
Talks that score highly with pupils are informative and entertaining. Even though your presentation should make links to the exam specification that the students are following (teachers will be happy to advise) they expect that a talk will be different from a lesson. The latter are often presented as logical expositions. However, scientific problems often appear as puzzles and solving a puzzle is an excellent way to stimulate and maintain interest.
Avoid jargon and acronyms at all costs. Split your story into self-contained chunks rather than one extended narrative. Recapitulate as you go along and keep referring to basic concepts. At the end, summarize the main points and conclusions.
Make sure you prepare thoroughly – even basic definitions of phenomena need rehearsing at least once as they appear in your script. Know your script inside out – ideally your delivery needs to be ad lib.
When you are presenting, try hard to keep eye contact with the audience for as much of the time as possible. Talk to them, not to the slides on the screen.
Your audience
School or college venues are more intimate than a university lecture hall. Your average audience member will recognize more of what they have already studied than they actually fully understand.
Regularly check your listeners sitting either side of the middle centre of the audience. In my experience, they are usually the ones who will be trying hardest to follow what you are saying. If they look confused you have probably lost most of your audience.
Consider audience participation. It could be as simple as asking them to vote, for example, on which outcome they expect from an experiment. Avoid passing things round as this can be a distraction. Similarly, any handouts are probably best left until the end, otherwise the listeners’ attention is divided.
How we can widen career aspirations for the next generation
Your PowerPoint
When composing PowerPoint slides, it is all too easy to put too much information onto each slide as you are by necessity sat close to your computer screen. Check each slide by viewing the screen from about 2.5 m away. Anything unreadable to you at this distance will also be unreadable to your audience when projected onto the average school’s screen. A good rule of thumb is to include no more than 25–30 words per slide.
The type of slide least liked by audiences is a list. So the golden rule is to keep it simple. PowerPoint works best when it adds visual material to punch home what you are saying. Pictures are worth a thousand words and are a genuine visual aid – but do not use clip art just for the sake of having an image.
Redraw and simplify complex diagrams and graphs from scientific papers. Remove all but essential text. Make sure that important features such as lines on graphs are clearly visible. Always tell an audience what is plotted on each axis. Build up diagrams and formulae one element at a time. An easy way to do this is to compose the last slide in a sequence first. Decide how many steps are needed, and make that number of copies of the last slide, plus an extra. Then edit backwards to the start of the sequence. This ensures that no information or steps are left out. The extra copy of the slide is there in case things go wrong, and can be deleted when you are satisfied with the sequence you have composed.
Keep the slide transitions simple. Cartwheeling text entering stage left is just a distraction. Avoid using the slides as a set of crib sheets for what you want to say. If necessary, use separate notes or the computer screen notes facility in PowerPoint. Insert a blank slide wherever you have something to say and don’t want the audience looking at the last or the next slide.
Don’t just rely on PowerPoint. Holding up a relevant physical object has much more impact. If you plan to do a demonstration, do make sure that it will be easily seen by the audience, and practise it beforehand to make sure it works reliably. Consider designing a demonstration that seems to go wrong in a way that emphasizes the point you are trying to make – this can be a real attention grabber and is likely to be memorable.
Medal-winning presentations
Your timing
Unless you invite questions, or encourage audience participation as you go along, 45 minutes is the benchmark. Any more and you will be pushing your audience’s attention span. Experience shows that questions at the end of a talk fill another 10 minutes or so, giving a total time of around one hour.
Giving a talk is a performance, so be a bit larger than life. Dramatic pauses raise expectations. Five seconds may seem like a long silence to you, but it’s not perceived like that by your listeners. Dwell on and talk about a slide for enough time for it to be taken in. Edit your talk in real time rather than rushing to cram it all in. Beware of speeding up as you get more practised at giving the talk.
Your response
Do be tolerant of inexperienced student chairpersons, regarding things like their introductions and votes of thanks.
Keep notes on what goes down well and what doesn’t (for example, whether the audience laughed at any jokes), and modify your subsequent talks accordingly. Aim to give your talk three or four times a year for at least two years, to make the effort of preparing it worthwhile. Actively seek out opportunities to present. When you feel you have a successful story to tell, why not consider turning it into an article for a magazine such as Physics Review so that it can reach a wider pre-university audience?
Finally, giving talks to young audiences is not something you necessarily learn to do well just by doing it. Feedback on your efforts is vital and should be solicited. You can do this by composing a short e-mail questionnaire and sending it to the organizer of your talk, asking, for example, whether the pace was too slow or too fast, whether the slides were suitable and visible, and whether you could be easily heard. Good luck.
